A polarizer is widely used as an element providing polarized light for a liquid crystal displaying apparatus, and as an element detecting polarized light. As such the polarizer, a polarizing film composed of polyvinylalcohol to which a protecting film composed of triacetylcellulose is adhered, has been previously used. However, recently, with expansion of a liquid crystal displaying apparatus in mobile equipments such as a note-type personal computer and a cellular phone, thin and light polarizer are desired. In addition, since a mobile equipments are use in various place due to portability, improvement of the durability is also desired.
However, in the previous method of adhering a protecting film composed of triacetylcellulose to a polarizing film, from a viewpoint of the handling during producing process and the durability, it is difficult to make thickness of a protecting film below 20 μm. In order to solve such the problem, for example, JP 2000-199819 A discloses the method of forming a protecting film which is thin and has the better durability, by coating a solution of a cyclic polyolefin on at least one side of a polarizing film composed of hydrophilic polymer, and drying it.
An object of the present invention is to provide a polarizer which is thin and light as well as has durability, and an optical member which is excellent in reliance and can form a liquid crystal displaying apparatus used in mobiles.